In recent years, every carbon fiber manufacturing has been a dream idea for every engineer. Invention of carbon fiber manufacturing was in the 1950s to strengthen high temperature cast plastic constituents on missiles. The first carbon fiber manufacture achievement came due to heating strands of rayon until carbonization took place.
Early 1960 was an important year in the carbon fiber manufacturing. This is when polyacrylonitrile was castoff as a raw material in this carbon fiber manufacturing. Through use of polyacrylonitrile, carbon fibers produced contained 55% carbon and good carbon fiber properties as of that time.
Later in 1970, there was a discovery of a new raw material in carbon fiber manufacturing. The discovery indicated use of petroleum pitch in production of carbon fiber. Carbon fibers produced using this raw material had 85% carbon and were stronger than carbon fibers produced using polyacrylonitrile. However, these carbon fibers had some degree of compression strength hence were not accepted.
Most of the western European countries, USA, and Japan are leading in the production of carbon fibers. Currently carbon fibers are playing an important role in the manufacturing of many products such as
- Bicycle frames
- Automobile springs
- Fishing rods
- Golf club shafts
- Racing car bodies
- Spacecraft and Aircraft parts
- Sailboard flag pole
Categories of Carbon Fibers
Tensile modulus is the main property in categorization of carbon fibers. There are three categories of carbon fibers. They include:
- Low Modulus. These carbon fibers have tensile modulus of lower than two hundred and forty million Kilo-Pascal.
- Standard Modulus.
- Intermediate Modulus.
- High Modulus.
- Ultrahigh Modulus. These carbon fibers contain tensile strength ranging from half a million to a billion Kilo-Pascal.
Looking at steel it has a tensile strength of two hundred million kilo-Pascal, comparing to the ultrahigh carbon fibers it is five times less strong.
Raw Materials used in Carbon Fiber Manufacturing
A precursor is the raw material used in manufacture of carbon fiber. Most of carbon fiber produced is from polyacrylonitrile. In addition, petroleum pitch or rayon make carbon fiber. In the manufacture of carbon fiber, there is use of a number of liquids and gases. All these have particular properties to attain.
Carbon Fiber Manufacturing Procedure
Carbon fiber manufacturing is divide into two:
- Mechanical part
- Chemical part
Drawing long components from the precursor then exposing them at high temperature ensuring there is no contact with oxygen. This is to ensure removal of non-carbon atoms guaranteeing the fiber is long and the carbon atoms are firmly inter-locked.
Procedure of using polyacrylonitrile
By mixing acrylonitrile plastic powder with methyl methacrylate and a catalyst in a conservative polymerization to form a polyacrylonitrile. Then rolling of polyacrylonitrile into fibers by use different procedures. One of the methods used in spinning is mixing the polyacrylonitrile with certain chemicals and traverse tiny jets into a chemical bath where it clots and hardens into fibers.
Another procedure is by heating polyacrylonitrile mixture while pumping it through tiny jets into a cavity where evaporation of the solvent takes place hence coagulating into fiber. Lastly, washing and stretching of the carbon fiber to achieve a certain diameter. This helps the carbon fibers molecule aligning and strong carbon bonding.
Before carbonization, the carbon fibers must to be transformed chemically to convert their atomic bonding to an additional thermally stable hierarchy bonding. This is done by heating the fibers in air for about two hours to a temperature of 200-300 degrees Celsius. The stabilizing procedure uses different equipment’s and techniques. Some procedures of carbon fiber production are strained in series of heated cavities.
Heating of the carbon fibers is done after carbonization at about 1000-3000 degrees Celsius for some few minutes in a heating system filled with non-oxygen gas mixture. This inhibits the carbon fibers combustion at high temperature. The gas mixture’s pressure in the heating system is higher than the atmospheric pressure. While heating the carbon fibers the non-carbons atoms are removed.
Some of the components in the gas mixture include:
- Carbon monoxide
- Water vapor
- Carbon (iv) oxide
During carbonization of the carbon fibers, you should pass them in two unlike heating systems in other different procedures.
When through with carbon fiber carbonization you are not allowed to mix it with composite materials. You need to provide the carbon fibers with enhanced bonding properties. If you want to achieve oxidation, you should pass the carbon fibers through the following gases or liquids:
- Carbon (iv) oxide
- Nitric acid
- Sodium Hypochlorite
During the carbon surface treatment, you should carry it carefully to evade surface flaws like pits that result in carbon fiber failure.
When you are through with surface treatment, you should coat the carbon fibers to avoid destruction from winding. You should pick the carbon fiber coating materials pick according to their compatibility with the epoxy resin used in materialization of the composite materials. When you are, complete wind the carbon fibers in bobbins and load it into a spinning machine to twist the carbon fibers into rolls of different sizes.
Many developing countries are embracing carbon fiber manufacturing. Nevertheless, during manufacturing there should be quality control measures put into consideration. They include:
- For proper quality control, you should produce a large amount of carbon fibers.
- When manufacturing carbon fibers you should consider variables like chemical composition, temperature, and time.
- When you are through, both carbon fibers and the composite materials should undergo thorough tests like sizing amount, strength, and density.
Supplier of advanced composite materials associations in 1990 came up with rules governing the carbon fiber manufacturing tests.
Apart from quality control, another important aspect n carbon fiber manufacturing is the safety and health fears. In all kinds of manufacturing processes, you should be keen on the health hazard. This is no different when it comes to carbon fiber manufacturing.
Health fears like inhalation of dust and skin irascibility are mainly of concern during carbon fiber manufacturing. Effects on the electrical tools is the major concern during this process. Carbon fiber is a good electricity conductor hence when particles of come into contact with some electrical equipment’s it may cause shorts or arcing. Hence, you should put the equipment’s in safe place to avoid contact with the carbon fiber particles.
Recently, manufacture of nanotubes revolution is through carbon fibers. If you want to study more on carbon fiber manufacturing, you should visit the following sites American Carbon Society or Carbon composites. In addition, you can read these books encyclopedia of chemical technology or materials handbook. The journal Physics today is also essential in carbon fiber manufacturing.